Hybrid I/O automata revisited

Abstract. In earlier work, we developed a mathematical hy-brid I/O automaton (HIOA) modeling framework, capable of describing both discrete and continuous behavior. This frame-work has been used to analyze examples of automated trans-portation systems, intelligent vehicle highway systems, air traf-fic control systems, and consumer electronics applications. Here, we reconsider the basic definitions of the HIOA framework, in particular, the dual use of external variables for discrete and continuous communication. We present a new HIOA model that is simpler than the earlier model, due to a clearer separa-tion between discrete and continuous activity.